Roof construction



March so 1926.. 1,579,016

. H. E. MARKS I V Filed April 20, '1925 Patented Mar. 30, 1926.

UNITED. "STATES,

PATENT-OFFIICEIP HERBERT n. M RKS, or GLEN osecaae, sEwIoknEY, PENNSYLVANIA,

noon .cons'riwo'rrou.

' Application filed Apri l 20, 1925. Serial m. 24,327.

To all whom it may concern.

Be it known that I, HERBERT E. MARKS, a citizen of the United States, and a resident of Glen Osborne, Sewickley, in thecounty of Allegheny and State of Pennsylvania,

' have invented a new and useful Improvement in Roof Construction, of which the following is a'specification'.

The invention relates to roofs which comprise spaced purlins and preformed slabs of ceinentitious material'supported at their ends by purlins, it being understood that the term purlins is here used to designate 'rafters,-and other equivalent members, for

supporting roof decks.

As customarily constructed, the entire up per faces of slabs for such roofs lie in acommon plane, and by reason of this, it has been necessary to provide them with thick bodies of waterproofing material, three" or four layers frequently being requlred to assure adequate protection against the ingress of water. Because of the amount of material ref quired, and of the labor cost of applying the waterproofing of such roofs is quite-expensive. Also, the plainness of the surfaces" of such a roof gives it an unattractive ap pearance. V

The object ofthis invention'is to provide a roof of the character explained which is so formed as to require a minimum of waterproofing, and less than heretofore required, and which is otherwise economical to construct; a roof which is strong-durable and sectional view corresponding to F ig'. 4 illustrating a modification of construction, and Fig. 6 a perspective viewof an'attaching clip.

In the practice of this invention, the pre formed slabs of cemen'titious material, whichmay be made of concrete, gypsum and the like, but which are preferably formed of gypsum, have their sides oif-set'to formgut ters between them. The slabs are provided on their upper or-exposed faces with layers of waterproofing material which may be applied in plastic form either before or after the slabs are laid upon aro'of, but whicharc preferably 111 the form of sheets attached to the slabs before they are laid. These layers of waterproofing material extend downward- 'ly over the gutter-forming sides ofthe slabs,

and monolithic bodies of cementitious material are formed in the gutters to a height sufiicient to seal the lower edges-of the layers of waterproofing material, but to a less height than th'e' tplane of the tops of; the slabs.

The bodies of cementitious material may be.

of concrete or gypsum, and may themselves be waterproof, although it is preferred to form the bodies" of ordinary concrete or gypsum, and to -provide their tops with waterproofing layers. Because the top of each slab is relatively"narrow, water "will readily flow from it into the gutters formed between the upper portions of the sides of the slabs and above the bodies of cementi ticus material molded between the sides of the slabs. Accordingly, relativelythin layers" of waterproofing material are required 1 for the topsofthe slabs. \Vhen the monolithic bodies of cementitious'material in the gutters are not formed of material which in itself is water resistant,'the layersof waterproofing material upon such bodies is heavier or thicker than that upon the tops of the slabs because water may remain in the gutt' The monolith-icbodiesof cementitious inaterial formed in the gutters' nay be -provided fwith reenfortementto cause such bodies to'actas beams] for strengthening the 1 slabsf However, the slabs may be inherently sufficiently strong-to support their own weight and that ofthe required roof load.1

For attaching thejslabs to purlins, clips are preferably arranged in the'lower portions of the gutters between the sides of the slabs and extend downwardly between the 'slabs, being constructed to engage. the flanges of purlins.- The upperfends of these clips are anchored in thebodies of cementitious material in the gutters. 1

Having reference now to theillustrative embodiment of the invention, Figjjl shows apluralit-y of slabs 1 resting at their ends uponthe top flanges of lpurlins 2 which ma I bechannels; The top of each slab is provided with a layer 3 of waterproofing material which extends downwardly over the sides of the slabs as clearly illustrated. The sides of the slabs may be variously off-set to form gutters 20 between them, the gutters illustrated in Fig, 2 being V-shapeol, and

those shown in Fig. 3 being reentrant. Each slab may be reenforced longitudinally by welded wire fabric having longitudinal strands arranged substantially in the positions indicated, and having transverse strands v 5- the ends of which preferably extend to a face of the slabs in order to support the. reinforcing while the slab, is be- V ingmolded.

As seen in Fig. 3, the bottoms of the slabs maybe hollowed to save material and make them light in weight.

lVhen the slabs have been laid upon the pur-hns, or while they are being so laid, purlin-attaching clips are arranged between their sides.. .lVhile various forms of clips may be used, a'suitable form is that illustrated in Fig. 6, and which comprises a short horizontal rod 6, the ends of which rest against the tapered or off-set. sides of the slabs to hold the upper end of the clip above. the bottom of the gutters, and a twisted bar 7 provided at its top with a loop 8 to engage rod 6 and provided at its lower endwith laterally extending lip -9 .for engaging the flange of, a purlin. When the bodies of cementitious material formed in the gutters are I reenforced, reenforcing rods 10 maybe supported'uponthe upper ends of the clips to. position them for encasement.

After the clips 7 and reenforcing bars 10.

are so positioned, bodies lliof cementitious material are formed in the gutters to a height above the lower edges of waterproofing-layers. 3, but below the planes of the tops ofthe slabs, thus forming water-receiving gutters between the slabs. In the embodiment of the invention illustrated in Fig. 2- the lower edges of the waterproofing layers extend but a short distance below the tops of bodies 11, whereas in Fig. 3 these edges extend nearly to the bottoms of the gutters and bodies 21 of asphalt or other waterproofing material are formed in the bottoms of the gutters to further seal the edges of the waterproofing layers, bodies 11 of cementitious material reenforced by rods tween the slabs make it possible to adequate 1y waterproof the tops of the slabs with layers of 'waterproofing material thinner than now required for plane-faced roofs, but the gutters break up the continuity of the roof, and thereby give it a pleasing appearance. If desired, the slabs may, as illustrated in Fig. 5, be provided at their ends with gutters .15, similar to those formed between their sides, .the tops of the gutters 15 being, in the same general plane as the tops of those formed betweenthe sides of the slab.v hen gutters 15 are formed between the ends of the slabs, the waterproofing layers 3 have their ends sealed in the same general manner as thesides,

According to the provisions ofthev patent statutes, I have explained the principle .and operation of my invention, and have illustrated and described what I now consider to. representits best embodiment, However, I desire to have it understood that, within the scope of the 'appended claims, the invention maybe practiced byother forms of construction than that particularly illustrated and described. Y

I claim as my invention:

1. A roof comprising spaced purlins, preformedslabs of-cementitious material supported at theirendsbythe purlins,the .upper portions of the adjacent sides of said slabsbeing offset to form gutters between the slabs, layers of waterproofing .material'covermg the tops of the slabs and extendingv downwardly over said gutter-forming sides ofthev slabs, and monolithic bodies of cementitious material formed in said gutters and vsealing the lower edgesof said waterproofing layers, the. tops .of said bodies .being. below-the plane of the tops of-the slabs and being waterproof. V

2. A roof comprising spaced pi1rlins,}preformed 1 slabs of cementitious. material supported at their ends by the purlins,.the upper portions of the adjacent sidesof said slabsbeing oflsetto form gutters between the slabs, layers of waterproofing material covering the" tops of the slabs and extending downwardly over saidgutter-forming sides of the slabs, and monolithiobodies of cemen titiousmaterial formed in said gutters and sealingthe lower edges of said waterproofing layers,,the tops of said bodies being below theplane of thetops of'theslabs and being provided with a heavier layer of waterproofing material than said layers of waterproofing material on said slabs. I 3. Aroof comprising spaced purlins, preformed slabsofcementitious material supported'at their ends by thepurlins, the upper, portions ofthe. adjacent sidesof said slabs being oiiset'to 'form gutters between tops and extending downwardly over their gutter-forming sides, reenforced bodies of cementitious material formed in said gutters and sealing the lower edges of said waterproofing sheets, the tops of said bodies being below the plane of the tops of the slabs and being provided with a layer of waterproofing material.

4. A roof comprising spaced purlins, preformed slabs of cementitious material supported at their ends by the purlins, the up per portions of the adjacent sides of said slabs being offset to form gutters between the slabs, layers of waterproofing material covering the tops of the slabs and extending downwardly of their gutter-forming sides, clips extending from the bottom portion of said gutters between the sides of the slabs and engaging said purlins, monolithic bodies of cementitious material formed in said gutters and encasing the upper ends of said clips to anchor them, said bodies sealing the lower edges of said waterproofing layers, and the tops of said bodies being-be: low the plane of the tops of the slabs and be ing waterproof.

5. A roof. comprising spaced purlins, preformed slabs of cementitious material sup ported at their ends by the purlins, the up-' per portions of the adjacent sides of said slabs being ofiset to. form gutters between the slabs, sheets vof waterproofing material attached to the slabs and covering their tops and extending downwardly over their gut ter-forming sides, clips extending from the bottom portions of said gutters between the sides of the slabs and engaging said purlins, reenforcing rods restingupon the upper ends of said clips, and monolithic bodies of cementitious material formed in said gutters and encasing the upper ends of said clips to anchor them and also encasing said reenforcing rods, said bodies sealing the lower edges of said Waterproofing sheets, and the .tops of said bodies being below the plane of the tops of the slabs and being provided with layers of waterproofing material.

In testimony whereof, I sign my name.

' HERBERT E. MARKS. 

